It is possible to collect data from sensor in RAM (or EEPROM) when no connection to blynk server and send it to server when internet is come back? Must be some format when I send not only data but data with timestamp I think.
I’m not aware of any such possibility. But it could be stored on some external media - be it SD card or HDD. But I don’t think it could be then send as a massive data chunk to server, when connection restores.
This has been discussed a few times elsewhere.
In a follow-up thread @Dmitriy said last month that maybe it was time to create an API for this…